Air circuit breakers as described within U.S. Pat No. 3,095,489 entitled "Manual Charging Means for Stored Energy Closing Mechanisms of Electric Circuit Breakers" and U.S. Pat. No. 3,084,238 entitled "Ratchet Mechanism for Charging a Closing Spring in an Electric Circuit Breaker" include operating mechanisms that are mainly exposed to the environment. Since the air circuit breakers are rated to carry up to several thousand amperes of current continuously, the exposure to convection cooling air assists in keeping the operating components within reasonable temperature limits.
Various accessory devices are used with such air circuit breakers to provide auxiliary function along with overcurrent protection. One such accessory is the bell alarm accessory that provides local and remote indication as to the occurrence of circuit interruption. U.S. Pat. No. 5,502,289 entitled "Bell Alarm and Lock-Out for High Ampere-Rated Circuit Breakers" describes a bell alarm accessory used with so-called "insulated case" circuit breakers wherein the circuit breaker interrupting components are completely enclosed within an insulating plastic enclosure.
U.S. patent application Ser. No. 08/875,595 filed on Jun. 19, 1997 entitled "Circuit Breaker Bell Alarm Accessory with Lockout" describes a bell alarm accessory for use with a high ampere-rated air circuit breaker that provides local as well as remote indication of such circuit interruption as well as preventing circuit breaker contact closure until and unless the bell alarm accessory has been manually reset.
High-ampere rated air type circuit breakers operate in the range of 2500 to 5000 amperes such that the large circuit breaker operating components are arranged with the bell alarm reset components in a particular manner. When low ampere-rated air type circuit breakers, that operate in the range of 150 to 1500 amperes, require bell alarms with lockout function to prevent contact closure until the bell alarm unit is reset, the arrangement of the circuit breaker smaller operating components do not allow the use of the high ampere-rated bell alarm reset accessory.
One purpose of the invention accordingly, is to describe a bell alarm accessory reset unit for use with low ampere-rated air type circuit breakers that prevents the circuit breaker contacts from becoming closed until the bell alarm module has become manually reset.